As he puts it, "We know when we come to work that there's the potential of the DEA coming through the door. But we go to work anyway."

Concerns about a potential federal crackdown on medical marijuana began rising following a memo by Oakland-area U.S. Attorney Melinda Haag, which seemed to contradict a 2009 advisory by Deputy AG David Ogden. The Ogden memo recommended that U.S. Attorneys not devote significant bucks on prosecuting medical marijuana operations following the law in states that approved them.

Inside a CDS center.

Then came yet another memo, this one from Deputy Attorney General James M. Cole, who attempted to clarify the Ogden missive. As we noted in our earlier post, the Cole document reiterates that "it is likely not an efficient use of federal resources to focus enforcement efforts on individuals with cancer or other serious illnesses who use marijuana as part of a recommended treatment regiment consistent with applicable state law, or their caregivers." But it also stresses that the term "caregiver" means "individuals providing care to individuals with cancer or other serious illnesses, not commercial operations cultivating, selling or distributing marijuana." In other words, a dispensary isn't a caregiver.

Additionally, the memo maintains that there has been "an increase in the scope of commercial cultivation, sale, distribution and use of marijuana for purported medical purposes. For example, within the past twelve months, several jurisdictions have considered or enacted legislation to authorize multiple large-scale, privately-operated industrial marijuana cultivation centers. Some of these planned facilities have revenue projections of millions of dollars based on the planned cultivation of tens of thousands of cannabis plants.

"The Ogden Memorandum was never intended to shield such activities from federal enforcement action and prosecution, even where those activities purport to comply with state law. Persons who are in the business of cultivating, selling or distributing marijuana, and those who knowingly facilitate such activities, are in violation of the Controlled Substances Act, regardless of state law. Consistent with resource constraints and the discretion you may exercise in your district, such persons are subject to federal enforcement action, including potential prosecution. State laws or local ordinances are not a defense to civil or criminal enforcement offederal law with respect to such conduct, including enforcement of the CSA."

Polis communications director Chris Fitzgerald didn't see the Cole memo as portending an imminent assault on medical marijuana in Colorado, and neither does Browne, marketing director for the four CDS outlets in Denver-metro and Boulder

"Ultimately, I think this is a response to what Oakland was trying to do," he says. "They were talking about 100,000-plant grows on a really industrial scale. But here, we have a state-regulated system where we have tracking manifests and every employee is on file. It's a very different scenario than we feel that memo was responding to."

Indeed, Browne believes state regulation provides people in the industry with "more protection than if we'd stayed under the caregiver model -- and we're glad we took part in the regulation process." He's confident the feds "understand how we've done things, as opposed to the collective businesses you see in California. We have a little more leverage."

Some of CDS' stock.

Of course, Browne knows "the Controlled Substances Act is ultimately the law of the land, and the federal government can come in and do whatever they like." However, "we feel there are definitely businesses that aren't doing things the right way, and ultimately, we think they'll be the targets" of possible prosecution. "Maybe they're people who never intended to see the application process through, or people who were letting things go out the back door."

That's not to say Browne thinks marijuana should be a top federal priority. "Ultimately, the DEA has a lot of hard work to do in this state dealing with drugs that do serious harm to people, and that's ultimately what their enforcement goals should be -- keeping Colorado safe from things like meth, cocaine and heroin. And I think they realize that as well."

In the meantime, conflicts continue to exist between state and federal laws, as evidenced by a ruling in Aspen that patient Nathan Benner can't use medical marijuana on probation. "None of that's been hashed out yet, no pun intended," Browne says. "But I think the important thing for patients to remember is that 1 percent of federal marijuana prosecutions end up in federal court, and the vast majority of those cases deal with people doing either distribution of large quantities of marijuana or people who have industrial-scale cultivation that's not under any kind of state guise. So I certainly wouldn't see this as a sky-is-falling moment for patients."

Moreover, he goes on, "if they want to prosecute a center in Colorado, they'll also have to prosecute the state employees who licensed us, the accountant we retained, and many other people. It's not as simple as saying it's just us. We're all part of a larger structure now, and even if we don't have a defense at a federal level, there'd certainly be an uproar. If that were to take place so close to an election, I think it would become a big issue."

Such factors could turn out to be the best security a Colorado center can have. Look below to read the entire Cole memo, which can also be accessed by clicking here.